3
This module creates an output raster map centered on the <em>x,y</em> values specified
4
with the <em>coordinate</em> parameter, out to the edge of the current region.
5
The output cell values increase linearly from the specified center. The <em>min</em>
6
and <em>max</em> parameters control the inner and outer output raster map radii, respectively.
8
<p>The <em>mult</em> parameter can be used to multiply the output raster cells by a common factor.
9
Note that this parameter does not affect the output raster position or size; only the z-values
10
are changed with this parameter.
11
<p>Binary-output raster maps (solid circles of one value) can be created
12
with the <b>-b</b> flag. Raster maps so created can be used to create
13
binary filters for use in <em>i.ifft</em> (inverse Fourier transformations;
14
apply filter with <em>r.mask</em>).
19
Generate a raster circle at current map center with a radius of 300m and outwardly
20
increasing raster values:
22
<div class="code"><pre>
23
EASTCENTER=`g.region -c | awk ' /center easting:/ { print $3 }'`
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NORTHCENTER=`g.region -c | awk ' /center northing:/ { print $3 }'`
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r.circle output=circle coordinate=${EASTCENTER},${NORTHCENTER} max=300
28
Generate a binary raster ring around current map center with an inner radius
29
of 500m and an outer radius of 1000m:
31
<div class="code"><pre>
32
EASTCENTER=`g.region -c | awk ' /center easting:/ { print $3 }'`
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NORTHCENTER=`g.region -c | awk ' /center northing:/ { print $3 }'`
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r.circle -b output=circle coordinate=${EASTCENTER},${NORTHCENTER} min=500 max=1000
40
<a href="g.region.html">g.region</a>,
41
<a href="g.remove.html">g.remove</a>,
42
<a href="g.rename.html">g.rename</a>,
43
<a href="i.fft.html">i.fft</a>,
44
<a href="i.ifft.html">i.ifft</a>,
45
<a href="r.mask.html">r.mask</a>
50
Bill Brown, U.S. Army Construction Engineering Research Laboratory<br>
51
Additional flag/min/max parameter by Markus Neteler, University of Hannover
53
<p><i>Last changed: $Date: 2014-12-12 00:16:30 +0100 (Fri, 12 Dec 2014) $</i>